Wood scraps which are discarded from truss plants and building construction sites, in the form of 2".times.4" and 2".times.6" pieces of framing lumber of varying lengths, currently are treated as waste material, resulting in a disposal problem. The handling of this waste material, namely its removal and disposition, is factored into construction costs. In large home development projects and truss plants, companies specializing in cleaning building sites generally are responsible for the disposal of the material. Such companies either haul this material into landfills or supply it to low-end users of wood products to get rid of it.
The low-end users of wood products vary throughout the United States, but one thing is in common. The common element is that low-end users do not have the ability to take the wood scrap material and convert it back into anything close to its original market value. As construction wood products become increasingly costly, partially as a result of limited available resources, the failure to recycle 2".times.4" and 2".times.6" scraps results in the loss of significant amounts of expensive materials.
Current low-end users of scrap wood are companies which produce mulch, pulp fiber, particle board and fuel for thermal energy generating stations. At the present time, the sale value of the reprocessed material into any of these uses does not result in a value of the material which exceeds over forty dollars per ton. This is significantly less than the original cost of the lumber in the form of 2".times.4" and 2".times.6" boards used in the construction of a home or other building.
The current end markets for wood scrap products and discarded wood material all require some separation by grade of material prior to its processing. In the manufacture of pulp paper, the scrap wood products are separated by grade and then are reduced to fiber as an additive for use in recycling and original paper manufacturing. In the manufacture of particle board, the wood scrap products are separated by grade and then are ground into utile form to produce particle board. For processing into mulch or agricultural products, the wood scrap products again are separated by grade and then are ground into mulch or added to other agricultural products. Finally, when wood scrap products are to be used for thermal energy generating facilities, it again is necessary to separate the wood scrap products by grade and grind the selected products into a form for use in such a thermal energy generating facility in the states which allow and permit the burning of organic material.
All of the foregoing current end uses of construction waste lumber in the form of waste scrap products result in a relatively low payout from the low-end users of these wood products for the raw material which is being converted into these different end uses. As a result, material handlers who remove such wood scrap products from a building site often find it most cost efficient simply to dispose of the material in a landfill, and ignore the secondary end users altogether.
Machines known as "finger joint machines" have been developed for processing random lengths of lumber into finished products, particularly for non-structural molding and trim for door openings, windows, chair rails and the like. When the finished product is to be painted, the fact that the molding or trim is comprised of a variety of different lengths of products which are joined together at glue joints by the finger joint machines is of no consequence. In factories which produce such molding from varying lengths of stock lumber, the lumber input for the finger joint machines is of consistent quality, that is, it typically is obtained from a single source and does not include defects of the type which could occur in construction site scrap lumber, such as broken ends, nails, non-square ends and the like. In addition the lumber employed in a typical finger joint factory is all of the same type and moisture content. Such lumber also is "new" lumber, which also makes its handling by a finger -joint machine relatively simple.
The two United States patents to Goss U.S. Pat. No. 2,300,728 and Forsythe U.S. Pat. No. 3,802,986 both are directed to the utilization of scrap lumber at a saw mill or manufacturing plant where the type of lumber, moisture content and dimensions are consistent. Such lumber does not include any defects, such as embedded nails or the like. The Goss patent discloses the use of a truck which delivers board pieces to a location where an operator visually inspects the pieces. The operator then operates a trim saw or cutoff saw to remove defects from the lumber and to square the ends of the pieces. From the this location, the lumber pieces then move to a machine which forms finger joints in them; and successive pieces are longitudinally formed together to form boards of commercial length. There is nothing in the Goss patent, however, to indicate that construction scrap from one or more sites can be processed together at a manufacturing location. The lumber which is utilized in the Goss system should be of consistent quality and dimensions, since it all is obtained from the sawmill or manufacturing plant itself. There is nothing in this patent which is directed to a construction waste wood or lumber recovery system or method.
The Forsythe patent is directed to a method and apparatus for producing lumber from short pieces at a lumber mill or the like. No utilization of scraps of varying parameters is suggested or disclosed in this patent. Trim saws are disclosed for squaring up the pieces and for removing defects. The system of Forsythe employs pre-heating of the lumber pieces; so that high moisture content boards may be used in the finger joint machine.
Three United States patents to Harwell U.S. Pat. No. 1,924,240; Nicholson U.S. Pat. No. 2,908,600; and Maier U.S. Pat. No. 4,128,119 are directed to machines or methods for joining short pieces of lumber to make longer pieces. Other U.S. patents directed to techniques for making finger joints are the patents to Strickler U.S. Pat. No. 3,262,723; Coombs U.S. Pat. No. 4,800,938; and Mountz U.S. Pat. No. 4,938,265. A U.S. patent to Schulte U.S. Pat. No. 4,565,597 discloses a technique for manufacturing a veneer web.
None of the above identified patents cover a system or method for converting discarded or scrap lumber building products back into something approximating its original sales/market value.
It is desirable to provide a system and method for recycling lumber wood scrap products of random lengths and of different species, with potentially different moisture contents, into framing lumber in an efficient and continuous manner.